Adding Equipment to the Outside
of Your Vehicle
Things you might add to the outside of your
vehicle can affect the airflow around it. This may
cause wind noise and affect windshield washer
performance. Check with your dealer before
adding equipment to the outside of your vehicle.
Fuel
Use of the recommended fuel is an important
part of the proper maintenance of your vehicle.
To help keep the engine clean and maintain
optimum vehicle performance, GM recommends
the use of gasoline advertised as TOP TIER
Detergent Gasoline.
The 8th digit of the Vehicle Identification Number
(VIN) shows the code letter or number that
identifies your vehicle’s engine. The VIN is at
the top left of the instrument panel. See Vehicle
Identification Number (VIN) on page 428.
Gasoline Octane
If your vehicle has the 3.8L V6 engine
(VIN Code 2), use regular unleaded gasoline
with a posted octane rating of 87 or higher. If the
octane rating is less than 87, you might notice an
audible knocking noise when you drive, commonly
referred to as spark knock. If this occurs, use a
gasoline rated at 87 octane or higher as soon
as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking,
the engine needs service.
If your vehicle has the 4.6L V8 engine
(VIN Code Y), use premium unleaded gasoline
with a posted octane rating of 91 or higher.
You can also use regular unleaded gasoline
rated at 87 octane or higher, but your vehicle’s
acceleration could be slightly reduced, and you
might notice a slight audible knocking noise,
commonly referred to as spark knock. If the octane
is less than 87, you might notice a heavy knocking
noise when you drive. If this occurs, use a gasoline
rated at 87 octane or higher as soon as possible.
Otherwise, you could damage the engine. If you are
using gasoline rated at 87 octane or higher and you
hear heavy knocking, the engine needs service.
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